Type Method

noiseFieldWithSmoothness:animationSpeed:

Creates a field that applies random forces to objects in its area of effect.

Declaration

+ (SCNPhysicsField *)noiseFieldWithSmoothness:(CGFloat)smoothness animationSpeed:(CGFloat)speed;

Parameters

smoothness

The amount of randomness in the field. A value of 0.0 specifies maximum noise, and a value of 1.0 specifies no noise at all.

speed

The field’s variation over time. Specify 0.0 for a static field.

Return Value

A physics field object. To use the field in a scene, attach it to the physicsField property of an SCNNode object.

Discussion

Use this field type to simulate effects involving random motion, such as fireflies or gently falling snow.

In calculating the direction and strength of the field’s effect on an object, SceneKit uses a Perlin simplex noise function. This function produces a velocity field that varies over time.

The default falloffExponent value for a noise field is 0.0, indicating that the field’s effect is constant throughout its area of effect. This field type ignores the field’s direction property.

See Also

Creating Physics Fields

+ dragField

Creates a field that slows any object in its area of effect with a force proportional to the object’s velocity.

+ vortexField

Creates a field whose forces circulate around an axis.

+ radialGravityField

Creates a field that accelerates objects toward its center.

+ linearGravityField

Creates a field that accelerates objects in a specific direction.

+ turbulenceFieldWithSmoothness:animationSpeed:

Creates a field that applies random forces to objects in its area of effect, with magnitudes proportional to those objects’ velocities.

+ springField

Creates a field that pulls objects toward its center with a spring-like force.

+ electricField

Creates a field that attracts or repels objects based on their electrical charge and on their distance from the field’s center.

+ magneticField

Creates a field that attracts or repels objects based on their electrical charge, velocity, and distance from the field’s axis.